1. Field of the Disclosure
This disclosure generally relates to an interactive device and, more particularly, to a displacement detection device and operating method thereof.
2. Description of the Related Art
As a wireless optical mouse does not have a signal line connected to a host, the operational convenience thereof is significantly improved. Especially for an input device of portable computers, the wireless optical mouse gradually replaces the conventional wired optical mouse. However, as the wireless optical mouse generally includes a plurality of active components such as a light source, a digital signal processor, an image sensor and a wireless transmission unit, the total power consumption is large and a service life of the battery is insufficient.
To solve this problem, conventionally it is able to change a sampling frequency and an exposure time of the image sensor so as to reduce the consuming power of a wireless optical mouse. However in practical use, this method can have at least the following problems. As the exposure time of the image sensor is changed with a moving speed of the wireless optical mouse, a total intensity of the image frame being captured can have a large variation resulting in a poor stability.
Another choice to reduce the power consumption of a wireless optical mouse is to change a lighting frequency of the light source. For example referring to FIG. 1, the lighting frequency of the light source may be fixed as 3000 frames/second, 1500 frames/second or 1000 frames/second according to the displacement of the wireless optical mouse. However, in this operating method different consumption current is required at different lighting frequencies, e.g. the consumption current in a high speed mode is triple times of that in a low speed mode.
Accordingly, the present disclosure further provides a displacement detection device and operating method thereof that may change a lighting pattern of the light source according to different displacement so as to further reduce the total power consumption of the displacement detection device.